When it has been desirable or necessary to remove gas bubbles from liquids flowing in closed systems, the art has employed devices known as bubble traps. One such need for a bubble trap has been removal of air bubbles from blood flowing extracorporeally through a dialyzer. A leak in the system where it is under negative pressure may cause such air bubble formation.
For example, Jeffery et al. U.S. Pat. No. 4,102,655 discloses a plastic bubble trap having a liquid inlet extending up through a container bottom and a liquid outlet extending downward through a container top, the outlet opening being lower in the container than the inlet opening. The top and the bottom are made of two injection molded polyvinyl chloride plastic pieces solvent bonded together. An additional opening in the top is connected to a pressure monitor.
A blood flow-through chamber used in a different application is shown in European Published Patent Application No. 0058325A1. This publication discloses a chamber made of blow molded plastic and having an inlet and an outlet near the bottom of the chamber and an indented side wall above the inlet to deflect the incoming fluid sideways to prevent frothing and to provide smooth flow. An outlet at the top of the chamber is for connection to a pressure monitor.